Everlasting battery breakthrough with nanowire material

Batteries with an almost unlimited life-span could soon become a reality thanks to a new nanowire-based material that doesn’t lose capacity over hundreds of thousands of recharge cycles.

The novel material, developed by a team from University of California, Irvine, uses manganese dioxide to protect golden nanowires in an electrolyte made of a Plexiglas-like gel.

In tests, the material demonstrated consistent capacity over 200,000 recharge cycles, potentially paving the way for smartphone and electric car batteries that would never need replacing.

“These things typically die in dramatic fashion after 5,000 or 6,000 or 7,000 cycles at most," said Reginald Penner, senior author of a study published in the latest issue of the journal American Chemical Society's Energy Letters.

Gold nanowires have been experimented with before for batteries, but scientists usually found that the filaments - thousands of times thinner than a human hair - tend to crack and grow brittle with repeated charging and discharging.

This has been a major obstacle for practical applications that would utilise the nanowires' ability to store and transfer electrons over their large surface area.

Penner, who oversaw the experiments of PhD student Mya Le Thai, said the discovery was made by chance.

"Mya was playing around and she coated this whole thing with a very thin gel layer and started to cycle it," said Penner, chair of UCI's chemistry department. "She discovered that just by using this gel, she could cycle it hundreds of thousands of times without losing any capacity."

The researcher explained that the gel makes the nanowires more flexible, which prevents cracking.

"The coated electrode holds its shape much better, making it a more reliable option," Thai said. "This research proves that a nanowire-based battery electrode can have a long lifetime and that we can make these kinds of batteries a reality."

The study was conducted in coordination with the Nanostructures for Electrical Energy Storage Energy Frontier Research Center at the University of Maryland, with funding from the Basic Energy Sciences division of the US Department of Energy.